Hammer rotor type bradford crusher



Unite HAMMER RoToR TYPE BRADFORD cRUsHER Forest H. Neely, Philadelphia, Pa., assignor to Poor & Company, Chicago, lll., a corporation of Delaware This invention relates to an improvement in crushers of the Bradford type with internal hammer rotors and has particular reference to a construction utilizing an extended rotor journalled at both ends and a tramp iron arrester which prevents foreign material from reaching the rotor.

Hammer rotor type Bradford Crushers have customarily employed breaker units cantilevered into one or both ends of the screening cylinder. Because of the character of the work imposed on rotors of this type, they are necessarily relatively short. If made of extended length, the unsupported end would be subjected to undesirable thrust and unstable forces.

One of the objects of the present invention is to provide a hammer rotor of substantially twice the length of rotors previously employed, said rotor having bearing supports at both ends as distinguished from a support only at one end and cantilevered into the cylinder, thereby eliminating cantilever rotor wobble which causes vibration.

A further object is to utilize the innerl support for the rotor shaft in a manner to stiften the cylinder and thereby make cylinders of greater length. Also this support divides the cylinder into a preliminary screening chamber and a hammer chamber while at the same time cooperating with means for protecting the hammers from damage by tramp iron. That is to say, the 'support serves as an abutment for a tramp iron arrester in the respect, that, as the material is fed through the screening chamber toward the rotor chamber heavy foreign material will be retarded and fall back into the screening chamber where it will automatically collect and may be later removed by a man entering the open end of the screening chamber and shoveling it out.

A further object of the invention is to simplify the construction in the respect that only rotor drive is required at one end of the machine, thereby increasing the eciency and capacity of the machine and resulting in lower cost per ton operation.

With the -above and other objects in View which will more readily appear as the nature of the invention is better understood, the same consists in the novel construction, combination and arrangement of parts hereinafter more fully described, illustrated and claimed.

In the accompanying drawing:

Fig. 1 is a more or less diagrammatic sectional View of a screening cylinder and rotor supported at both ends within one end of the cylinder.

Fig. 2 is a vertical cross sectional view along the line 2 2 of Fig. 1. l

Similar reference characters designate corresponding parts throughout the several figures of the drawing.

It will be observed from Fig. l, the perforated cylinder A is mounted on external bearings B and C for rotation Within an appropriate housing D. ln accordance with Bradford type breaker practice, the interior of cylinder A is provided with staggered inclined feeding blades E thereby to assist in the movement of material supplied arent O ICC through the feeding means F toward the opposite end of the cylinder. p

The interior of cylinder A is, according to the present invention, divided into a screening chamber G and a hammer chamber H by a cylinder stiffening and rotor support or spider. This spider is in the form of a ring 1 having arms or spokes 2 leading to a central bearing 3 which supports the inner end of a rotor shaft 4 whose opposite end 5 is journalled at or near the external bear'- ing C. v.

The shaft 4 is provided with hammers 6 which operate in the customary fashion, but, because the shaft 4 is supported at both ends the number of hammers as well as the length of the shaft may be increased to give added breaking capacity. As will now appear suitable means is provided in conjunction with the ring 1 of the spider to protect the hammers against damage from heavy objects in the material being processed,

The material fed into the cylinder A and advanced by the elements E toward the ring 1 makes its way into the rotor chamber H after passing over a tramp iron arrester 7, disposed at the threshold of the chamber H, in such a way as to restrain the movement or travel of heavy pieces of material and cause it to slide back into the chamber G. To accomplish this action while the cylinder and rotor are in operation, the arrester 7 is provided with an inclined ramp face, that is, a face disposed at lsuch an angle to the line of feed between chambers G and H as to continuously arrest and direct backwardly by a more or less' retrograde movement, as the cylinder rotates, large pieces of material including so called tramp 'metal and other objects which tend to damage the rotors, while permitting the lighter material to pass over the ring into the hammer chamber H.

It will thus be seen as the coal or other material is fed into the chamber G and is impelled toward the chamber H, it will be fed through the spider 1 over and across the arrester 7. The material passing over the arrester will be carried upwardly by the elements E in the usual fashion and treated by the hammers 6 to continue the processing of the material to the point where it is reduced to usable fineness.

lt will now be apparent that the present invention provides bearing supports for both ends of the rotor shaft J4 and also protects the hammers from damage by heavy irreducible objects. The manner of mounting the shaft 4, particularly due to the spider, results in improved bearing loading in the respect that the main rotor load is equally distributed between the bearings at 3 and 5, respectively.

The present invention preserves all of the advantages of the Bradford type breaker and eliminates the objections with the result of greatly improved and more economical operation.

The present construction has other advantages over a mill of the center feed type. While units of this type have their place in certain environments, nevertheless due to the fact that the screening chamber of the present construction is fed only at one end there is a considerable reduction in vertical height which enables the present device to be used Where head room is a factor. Moreover, the internal bearing support, or the spider as it is termed herein, for the hammer rotor will strengthen the medial portion of the cylinder thus enabling greater cylinder length where desired, while, at the same time keeping the load nearer the bearings and not in the center of the cylinder as is the case in a center feed construction.'

In a unit of the center feed type, heavy, uncrushable materials are delivered to both ends for discharge. It is then necessary, by belt or gravity chutes, to join these two refuse streams into one refuse hopper. In the present case all except the heaviest refuse will be discharged at one end, thussimplifying removal.` Accms to the internal area of a cylinder of the center feed type must be through the center of the unit which is more dilicult than through .a door at the feed end of a unit of the present type. There is insufficient head room at the ends of center feed units .to allow for a walk-in maintenance entrance.

The construction herein, with the extended hammer frotors, will have the same screening area as a center Afeeduuit of comparable size. However, by concentrating fthe veffect of hammer action in one double length rotor area increased capacity is attainable.

I claim:

1. In a hammer rotor type Bradford Crusher, the combination, including, a perforated screening cylinder, a spider dividing the cylinder into an initial screening chamber to receive bulk material and a hammer chamber .downstream of the screening chamber, a rotary hammer in the hammer chamber, said hammer including a shaft having its inner end journalled in the spider and its outer end journalled outside the chamber, and means at the exit side of said screening chamber for arresting the movement of tramp iron and preventing the same from entering the hammer chamber to protect the hammers 0f the rotor.

2. In a hammer rotor type Bradford crusher, the combination, including, a perforated screening cylinder, a spider dividing the cylinder into a chamber to receive the bulk material tovbe crushed and a hammer chamber in receiving relation to said screening chamber, a rotary hammer including a shaft having its inner end journalled in the spider and its outer end journalled in a bearing arranged externally of the cylinder, and an inclined annular ramp pitched toward the rotor chamber and at the threshold of the hammer chamber for arresting themovement of tramp iron and heavy particles and holding them in the screening chamber for manual removal.

References Cited in the le of this patent UNITED STATES PATENTS 1,744,028 Borton lan. 2l, 1930 1,770,977 Fowden July 22, 1930 1,784,039 Braun Dec. 9, 1930 1,859,560 Hartshorn May 24, 1932 1,966,312 Rafetto July 10, 1934 2,708,075 Danyluke May 29, 1952 

